John has been having difficulties getting out of bed, is not interested in going out with friends, and does not even answer the phone. He has let a number of bills go unpaid, he is sleeping 12 to 14 hours a day, and he cannot concentrate at work. He has called in sick to work at least once each week. John is MOST likely suffering from _____ disorder. Please type the correct answer in the following input field, and then select the submit answer button or press the enter key when finished.